“阿尔杰姆煤炭”联合公司鲁缅采夫矿井850米水平上的“普加契夫卡-东”突出危险煤层是作为“伊兹维斯特尼亚奇卡”煤层l_6的解放......

The situation of mine development in coal industry of China and the method of shaft freezing in the type of double ring ......